CAJ | 학술논문

采用雾化粉体＋挤压（Ato ＋Ext）、雾化粉体＋热等静压＋挤压（Ato ＋HIP ＋Ext）、低温球磨＋挤压（Cryo ＋Ext）、低温球磨＋热等静压＋挤压（Cryo ＋HIP ＋Ext）四组不同的工艺制备块体纳米晶／细晶铝，并测定了室温拉伸性能，分析了这些块体材料的拉伸应力-应变曲线，利用透射电镜和扫描电镜观察了试样断口附近的位错活动及试样的断口形貌，讨论了其变形机理和断裂机理。研究结果表明：球磨粉体制备的块体纳米晶铝的强度远高于雾化粉体制备的块体超细晶铝，四组块体材料在拉伸过程中均不存在加工硬化现象；块体超细晶铝在拉伸过程中发生了明显的位错运动，对于块体纳米晶铝，尺寸≤100nm 的晶粒在拉伸过程中内部基本不发生位错运动；块体超细晶铝大部分区域发生穿晶断裂，而块体纳米晶铝基本发生沿晶断裂。
채용무화분체＋제압（Ato ＋Ext）、무화분체＋열등정압＋제압（Ato ＋HIP ＋Ext）、저온구마＋제압（Cryo ＋Ext）、저온구마＋열등정압＋제압（Cryo ＋HIP ＋Ext）사조불동적공예제비괴체납미정／세정려，병측정료실온랍신성능，분석료저사괴체재료적랍신응력-응변곡선，이용투사전경화소묘전경관찰료시양단구부근적위착활동급시양적단구형모，토론료기변형궤리화단렬궤리。연구결과표명：구마분체제비적괴체납미정려적강도원고우무화분체제비적괴체초세정려，사조괴체재료재랍신과정중균불존재가공경화현상；괴체초세정려재랍신과정중발생료명현적위착운동，대우괴체납미정려，척촌≤100nm 적정립재랍신과정중내부기본불발생위착운동；괴체초세정려대부분구역발생천정단렬，이괴체납미정려기본발생연정단렬。
In this study,four groups of different process es of Ato +Ext,Ato +HIP +Ext ,Cryo +Ext and Cryo +HIP +Ext were set to prepare bulk nanocrystalline /ultrafine-grained Al,and the mechanical properties of the bulks were determined.Then,tensile stress was analysized,the fracture morphology and corresponding dislocation morphology were observed respectively by scanning electron mi-croscopy (SEM).Finally,the deformation and fracture mechanism were discussed.The result showed that the sample made with as-milled powder had an excellent strength compared to sample made with atomized powder.The indication of work hardening had not been observed in all tensile stress strain curves of the four samples.The dislocation movement,which could been seen obviously in ultrafine-grained samples,appeared only in large grain(≥ 100nm)in nanocrystalline samples.The tensile specimen of the bulk prepared via Ato +HIP +Ext exhibited a transcrystalline fracture,while intergranular fracture was happened to the other specimens.